Iron chelation therapy elicits innate immune control of metastatic ovarian cancer

Iron accumulation in cancer cells contributes to malignant progression and chemoresistance. While disrupting this process can influence various hallmarks of cancer, the immunomodulatory effects of chelating iron in tumors remain undefined. Here, we report that treatment with deferiprone, an FDA-approved iron chelator, elicits innate immune responses that control metastatic ovarian cancer. Deferiprone reprogrammed ovarian cancer cells towards an immunostimulatory state characterized by enhanced production of type I interferon (IFN) and surface overexpression of molecules that activate natural killer (NK) cells. Mechanistically, this reprogramming was driven by innate sensing of mitochondrial DNA in the cytosol and concomitant activation of nuclear DNA damage responses evoked upon iron chelation. Deferiprone administration synergized with chemotherapy and prolonged the survival of mice bearing metastatic ovarian cancer by bolstering intratumoral NK cell infiltration and type I IFN responses. Iron chelation may represent an alternative immunotherapeutic approach for malignancies that are normally refractory to T cell-centric modalities.